This invention relates to a lock cylinder for a safety lock with a cylinder housing and a cylinder plug. The invention relates more particularly to such a lock cylinder provided with tumblers in the form of plug pins and housing pins, the tumblers being aligned by a key inserted into the lock. Each row of housing pins is mounted with its pin springs in a separate chamber, the chamber being mounted in turn in a recess in the cylinder housing.
In cylinder locks with lock cylinders of conventional design, the cylinder housing and cylinder plug are provided with drilled guide channels for the pin tumblers. In order for the individual housing and plug pins to cooperate smoothly, such safety cylinders must be manufactured with great precision and consequently are expensive.
It is also known from German Pat. No. 551,304 to arrange the housing pins with their associated springs in a separate chamber, the chamber being mounted in turn during assembly in a recess in the cylinder housing, the chamber being inserted in the bore of the cylinder housing and then pressed radially outward into the corresponding recess. However, this design likewise requires high precision and is costly.
In order to make the manufacture of lock cylinders more efficient, attempts have also been made to make the cylinder housing and cylinder plug in the form of a number of parts, e.g. to divide them longitudinally, so that the parts can be manufactured by stamping or casting methods. However, experience has shown that it is nearly impossible to satisfy the requirements relating to safety when the lock cylinders have been assembled, since the tolerance of the individual parts results in excessive variations from the desired parameters during assembly. These are manifested by jamming of the cylinder plug and excessive resistance to the insertion and withdrawal of the key.